Improvement in locks for prison-doors



IUNITED STATES PATENT OEEIGE.

L. HAM, OF'BOSTON, MASSACHUSETTS.

IMPROVEMENT IN LOCYKS FOR PRISION-DOORS.

Specification forming part of Letters Patent No. 89,830, dated May 4, 1869.

and use my invention. I will proceed to describe its nature, construction, and use. Y

The nature .of my invention consists, first, 1nv combining with avlock-casing for prisondoors a latch-lock and a peculiarly-for|ned catch, arranged so as to work together as a springlock of great security second, in combmlng with the casing a strong guard, which extends over the face of the catch and immediately behind thebar of the door, so that said bar cannot` be raised out of jaw of the catch.

Drawings. Figure 1 is an isometric perspective view of the casing, broken into to show the interior.

to hold it in a position represented by full lines, Figs. l and 2, when locked. AE, Figs. 1 and 2, is a latch-lock, the latch H of which serves to hold the arm, and consequently the catch L, as above stated.

If the latch be withdrawn it will be seen that the catch L4 will be free to assume the position represented by dotted lines, Fig. 2.

O, Fig. 2, represents the iron bar which forms the edge of the door, and .when the door is closed is held in the recess of the catch between the lipsl Z', as represented in Fig. 2.

Y To unlock the door Ihave vto simply withdraw the latch H, which action will allow the catch to swing around, as represented by theV dotted lines, and to leave the bar 0 free.

The contacting faces of H and K are rounded or beveled, as shown' in the drawings, so that when the catch L is unlocked the ,closing of thel cell-door will, by the action oi' the bar O.

against the lip l', cause the catch to swing backinto the position represented by full lines, Fig. 2-that is, the arm K coming in contact with the latch H will push it back, and, having passed beyond it, will allow it to snap out again, and thus to hold it until it is again released by the withdrawal of the latch H.

N is a guard, formed as represented in the drawings, which, bein ga part of the lock-casing, serves to prevent the. bar O of the door from being pried away from the lips H of the catch.

l The faceplate A D is attached to the lockcasing by means of a bracket, V, which hooks onto the bead W, Figs. 2 and 3, and also by the screws S S, Figs. 1 and 3. These screws are inserted through holes Z Z( made in' the guard N. (Shown in Figs. 1 and 3.) When the door is closed the bar O covers the heads of these screws S S, so that they are inaccessible.

` That I claim as my invention is- 1. Combining with an ordinary latch. or lock, E, the catch L, made and arranged substantially'as described, and for the purpose set forth.

2. The guard N of the lock-casing B C, in combination with the bar O and catch L, constructed and arranged substantially as described, and for the purpose set forth.

L. M. `HAM.

Witnesses WILLTAM EDsoN, FRANK G. PARKER. 

